AGAR AND CARRAGEENAN What do carrageenan and agar have in common? 1. Think about the chemical structure of carrageenan and agar - what do they have in common? 2. What are the differences between kappa, iota and lambda carrageenan? Why? Solution 1. Carrageenan structure is made up of linear galactan polysaccharides which are extract from the red algae seaweed that have sulfate content of 15-40%. Agar is related structurally to carrageenan, this polysaccharide derived from certain species of red algae contains sulfated galactose monomers. 2. The repeating units and the sulphate content are different for each type of carrageenan which is kappa, iota and lambda. For kappa carrageenan, the repeating unit is D-Galactose-4-Sulfate linked with 3,6-anhydrous-D-Galactose, with 25% of sulphate content approximated where as for iota carrageenan, the repeating unit is D-Galactose-4-Sulphate linked with 3,6-anhydrous-D-Galactose-2-Sulphate, with 32% of sulphate content approximated. At last for lambda carrageenan, the repeating unit is D-Galactose-2-Sulphate and D-Galactose-2,6-Disulphate, with 35% of sulphate content approximately. It is because many red algae species produce different types of carrageenans during their developmental history. They are also different on solubility in cold water. Kappa and iota carrageenan are not soluble in cold water whereas only lambda carrageenan is soluble in cold water. It is because it depends of cation which is combined with the carrageenan in cold water. GELATIN 1. In recent years a lot of efforts have been initiated to find new alternatives for gelatin? Why? 2. Gelatin is always considered a special/unique ingredient that find many applications in food and non-food industry. Why? 3. Do you think fish gelatin can be used to replace mammalian gelatin (porcine and bovine)? Solution 1. i) The mid-1990s witnessed a widespread health scare and concern in the world beef industry stemming from the emergence of the neurological disease called Bovine Spongiform Encephalopathy(BSE). ii) Judaism and Islam forbid the consumption of any pork-related products. iii) Since the late 1980s, the three East African countries of Uganda, Kenya, and Tanzania have witnessed a boom in the export of fresh water fish species to the international market, especially the European Union ang the United States. Because the fish is exported mainly in the form of “skinless” fish fillets, there is an abundance of fish skins and bones that could be used as sources of gelatin.
2. i) High quality gel in dilute solution with the clean ‘melt in mouth’ (melting point <37degree Celsius)
ii) At high concentration, it gives elastic gum like texture which slowly dissolve in mouth. iii)It is an effective emulsifying and foaming agent. iv) As polyelectrolyte, it is able to flocculate suspended particles. 3. Yes
ACTIVITIES
AGAR AND CARRAGEENAN
What do carrageenan and agar have in common?
1. Think about the chemical structure of carrageenan and agar - what do they have in common?
2. What are the differences between kappa, iota and lambda carrageenan? Why?
Solution
1. Carrageenan structure is made up of linear galactan polysaccharides which are extract from the red algae seaweed that have sulfate content of 15-40%. Agar is related structurally to carrageenan, this polysaccharide derived from certain species of red algae contains sulfated galactose monomers.
2. The repeating units and the sulphate content are different for each type of carrageenan which is kappa, iota and lambda. For kappa carrageenan, the repeating unit is D-Galactose-4-Sulfate linked with 3,6-anhydrous-D-Galactose, with 25% of sulphate content approximated where as for iota carrageenan, the repeating unit is D-Galactose-4-Sulphate linked with 3,6-anhydrous-D-Galactose-2-Sulphate, with 32% of sulphate content approximated. At last for lambda carrageenan, the repeating unit is D-Galactose-2-Sulphate and D-Galactose-2,6-Disulphate, with 35% of sulphate content approximately. It is because many red algae species produce different types of carrageenans during their developmental history.
They are also different on solubility in cold water. Kappa and iota carrageenan are not soluble in cold water whereas only lambda carrageenan is soluble in cold water. It is because it depends of cation which is combined with the carrageenan in cold water.
GELATIN
1. In recent years a lot of efforts have been initiated to find new alternatives for gelatin? Why?
2. Gelatin is always considered a special/unique ingredient that find many applications in food and non-food industry. Why?
3. Do you think fish gelatin can be used to replace mammalian gelatin (porcine and bovine)?
Solution
1. i) The mid-1990s witnessed a widespread health scare and concern in the world beef industry stemming from the emergence of the neurological disease called Bovine Spongiform Encephalopathy(BSE).
ii) Judaism and Islam forbid the consumption of any pork-related products.
iii) Since the late 1980s, the three East African countries of Uganda, Kenya, and Tanzania have witnessed a boom in the export of fresh water fish species to the international market, especially the European Union ang the United States. Because the fish is exported mainly in the form of “skinless” fish fillets, there is an abundance of fish skins and bones that could be used as sources of gelatin.
2. i) High quality gel in dilute solution with the clean ‘melt in mouth’ (melting point <37degree Celsius)
ii) At high concentration, it gives elastic gum like texture which slowly dissolve in mouth.
iii)It is an effective emulsifying and foaming agent.
iv) As polyelectrolyte, it is able to flocculate suspended particles.
3. Yes